As can be seen from FIGS. 8 and 9, a conventional light-guiding unit 5 for connector includes more than one light guiding post 51. Each of the light guiding posts 51 is made of a light transmitting material. When the light-guiding unit 5 is mounted to a connector case, light beam from a light source can be guided by the light guiding post 51 to a light-output end thereof.
Since the light guiding posts 51 are made of a light transmitting material, when the light beam emitted from a light-emitting element 6 corresponding to a first one of the light guiding posts 51, either a left one or a right one, enters the light guiding post 51, the light beam is subject to light loss when propagating along a path defined in the light guiding post 51. Part of the lost light beam is received by the second light guiding post 51 that does not receive a light beam from a light source thereof. That is, the second light guiding post 51 is interfered by the light beam propagating in the first light guiding post 51. As a result, both of the two light guiding posts 51 are lightened at their light-output end, which will cause error determination by a user using the connector. On the other hand, when the two light guiding posts 51 on the light-guiding unit 5 guide light beams at the same time, light beams from the two light-emitting elements 6 separately corresponding to the two light guiding posts 51 are also subject to light loss during propagating in the light guiding posts 51, so that the two light guiding posts 51 mutually interfere with each other. Under this situation, light beams could not be stably and exactly guided to the light-output ends of the two light guiding posts 51, and only a relatively weak light can be seen at the light-output ends. Therefore, the light-guiding unit 5 fails to perform its light guiding function in practical use thereof.
It is therefore desirable to develop a light guiding structure for connector that can stably and exactly guide light beams to avoid possible error determination by a user due to weak light shown at the light guiding posts.